[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
2 P" Y) {3 h  M4 j" A但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
3 r9 c$ |  P6 y' c$ g' b  l(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

我的计算机用的是intel的ICH7南桥。
0 I0 I- y! A- \0 m在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
FWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
The IDSEL programmed in this field addresses the following memory ranges:
FF70 0000h – FF7F FFFFh
3 {, \- X, f0 G' ~( [FF30 0000h – FF3F FFFFh
4 m' B2 M2 o3 e2 P) T+ }8 N在这里 IDSEL 如何理解。
* L4 J( G9 t) j" x" CFWH_DEC_EN1—Firmware Hub Decode Enable Register
, k" K* T6 ?& F5 k(LPC I/F—D31:F0)
7 |; [# G4 [! t3 {7 VFWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
7 F  H$ P; M8 q0 = Disable.
  A4 c1 j3 l/ t% a# E1 = Enable the following ranges for the Firmware Hub
/ r( q2 [. l) ~3 v% `6 X  zFF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
+ a( H* W# j' X  k# ]除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？

谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
1 X3 @* z, ]% n7 i6 b! iThis one clock field is used to indicate which of multiple Firmware components is being selected.
The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
decode the cycle to determine which bytes are requested on a read or which bytes to update on a
write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
+ A+ q$ `3 I9 \% c: Q3 h  ha standby power state.

详见LPC spec:
9 l$ @4 l+ Y( `1 c. S2 Thttp://www.intel.com/design/chipsets/industry/25128901.pdf

在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.